William J. Treytl

Alpha decay of neutron deficient astatine isotopes

Abstract Isotopes of astatine lighter than mass 205 were studied at the Heavy Ion Linear Accelerator by bombardment of 185Re and 187Re with 20Ne, using Si (Au) surface barrier detectors in on-line measurements. Mass number assignments of astatine 201 through 196 are based on excitation functions and on genetic relationships with polonium isotopes. Accurate alpha energies are reported for 204At through 196At, for 202Po through 194Po and for four light bismuth isotopes. Half-lives are given for 202At through 196At, and for the bismuth isotopes. Isomerism was detected in 202At, 200At and 198At.

Alpha decay of neutron-deficient francium isotopes

Abstract Isotopes of francium lighter than mass 214 were studied at the Heavy Ion Linear Accelerator by bombardment of 197 Au with 16 O and of 205 Tl with 12 C. Si(Au) surface-barrier detectors were used in on-line measurements to determine α-decay energies and half-lives. Mass number assignments of francium-213-203 were based on excitation functions and on genetic relationship with emanation and astatine isotopes. Isomerism was detected in 204 Fr. Results are compared with previous work by Griffioen et al.

Levels of 208Po from radioactive decay and nuclear reaction γ-ray spectroscopy

Abstract Information obtained from a study of the radioactive decay of 1.7 h 208 At and from on-line studies of the γ-radiations emitted by 208 Po produced in 209 Bi(p, 2n), 206 Pb(α, 2n) and 208 Pb(α, 4n) reactions has been used to construct a decay scheme for 208 At and a level scheme for 208 Po. Many of the low-lying levels can be explained on the basis of the known levels of 208 Pb and 210 Po and the weak coupling approximation. Among the interesting features of the scheme is a 380 nsec state which is identified as the 8 + member of the band of levels resulting from the proton configuration ( h 2 3 ) 2 .